Originally Posted by
FWAAA
Not sure the bolded part is gonna happen even if US and AA combine. IIRC, when AA acquired TWA, the TWA account balances (unspent miles) were converted to AA miles and added to the AA lifetime counter. But I don't think that previously redeemed TWA miles were added to AA's lifetime counter.
To add yet another wrinkle, AA changed its lifetime Gold/Plat counters last year so that only Butt in Seat miles count toward lifetime status.
Who knows what they will do, but US does award lifetime Silver at 1MM, so I would guess they would have a way to combine lifetime flight miles on US with lifetime flight miles on AA.
That being said, this is putting a cart several counties in front of a horse.